The robot is a Knightscope security robot, used by several Californian shopping centres for security. It's designed to identify anomalies in its environment, and then alert other (human) guards to any security threats.

While some mourned the passing of 'Steve the robot', others used the droid's untimely end to take down Elon Musk's predictions that artificial intelligence poses a fundamental threat to humanity.

Of course, it's more likely that the security bot simply didn't detect the body of water -- which is only slightly below ground-level -- as anything other than solid ground, and so drove straight into it.

The Knightscope's company website says the security robots' "autonomous presence" allows them to "guide themselves through even the most complex environments" -- but not, apparently, bodies of water.

In April this year, one of the 136-kilogram security guards was knocked down by a drunk man in Silicon Valley while patrolling the Knightscope offices. And last year, the same kind of robot knocked down and then ran over a toddler at a California mall.

At the time, Knightscope vice president of marketing and sales Stacy Dean Stephens defended the robots as "incredibly safe" -- but not, it would seem, for their own self-preservation.